nl80211: Optional IEs into scan request
[linux-2.6.git] / net / mac80211 / scan.c
1 /*
2  * Scanning implementation
3  *
4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5  * Copyright 2004, Instant802 Networks, Inc.
6  * Copyright 2005, Devicescape Software, Inc.
7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  */
14
15 /* TODO: figure out how to avoid that the "current BSS" expires */
16
17 #include <linux/wireless.h>
18 #include <linux/if_arp.h>
19 #include <linux/rtnetlink.h>
20 #include <net/mac80211.h>
21 #include <net/iw_handler.h>
22
23 #include "ieee80211_i.h"
24 #include "mesh.h"
25
26 #define IEEE80211_PROBE_DELAY (HZ / 33)
27 #define IEEE80211_CHANNEL_TIME (HZ / 33)
28 #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
29
30 struct ieee80211_bss *
31 ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
32                      u8 *ssid, u8 ssid_len)
33 {
34         return (void *)cfg80211_get_bss(local->hw.wiphy,
35                                         ieee80211_get_channel(local->hw.wiphy,
36                                                               freq),
37                                         bssid, ssid, ssid_len,
38                                         0, 0);
39 }
40
41 static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
42 {
43         struct ieee80211_bss *bss = (void *)cbss;
44
45         kfree(bss_mesh_id(bss));
46         kfree(bss_mesh_cfg(bss));
47 }
48
49 void ieee80211_rx_bss_put(struct ieee80211_local *local,
50                           struct ieee80211_bss *bss)
51 {
52         cfg80211_put_bss((struct cfg80211_bss *)bss);
53 }
54
55 struct ieee80211_bss *
56 ieee80211_bss_info_update(struct ieee80211_local *local,
57                           struct ieee80211_rx_status *rx_status,
58                           struct ieee80211_mgmt *mgmt,
59                           size_t len,
60                           struct ieee802_11_elems *elems,
61                           struct ieee80211_channel *channel,
62                           bool beacon)
63 {
64         struct ieee80211_bss *bss;
65         int clen;
66         enum cfg80211_signal_type sigtype = CFG80211_SIGNAL_TYPE_NONE;
67         s32 signal = 0;
68
69         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
70                 sigtype = CFG80211_SIGNAL_TYPE_MBM;
71                 signal = rx_status->signal * 100;
72         } else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) {
73                 sigtype = CFG80211_SIGNAL_TYPE_UNSPEC;
74                 signal = (rx_status->signal * 100) / local->hw.max_signal;
75         }
76
77         bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
78                                                 mgmt, len, signal, sigtype,
79                                                 GFP_ATOMIC);
80
81         if (!bss)
82                 return NULL;
83
84         bss->cbss.free_priv = ieee80211_rx_bss_free;
85
86         /* save the ERP value so that it is available at association time */
87         if (elems->erp_info && elems->erp_info_len >= 1) {
88                 bss->erp_value = elems->erp_info[0];
89                 bss->has_erp_value = 1;
90         }
91
92         if (elems->tim) {
93                 struct ieee80211_tim_ie *tim_ie =
94                         (struct ieee80211_tim_ie *)elems->tim;
95                 bss->dtim_period = tim_ie->dtim_period;
96         }
97
98         /* set default value for buggy APs */
99         if (!elems->tim || bss->dtim_period == 0)
100                 bss->dtim_period = 1;
101
102         bss->supp_rates_len = 0;
103         if (elems->supp_rates) {
104                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
105                 if (clen > elems->supp_rates_len)
106                         clen = elems->supp_rates_len;
107                 memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
108                        clen);
109                 bss->supp_rates_len += clen;
110         }
111         if (elems->ext_supp_rates) {
112                 clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
113                 if (clen > elems->ext_supp_rates_len)
114                         clen = elems->ext_supp_rates_len;
115                 memcpy(&bss->supp_rates[bss->supp_rates_len],
116                        elems->ext_supp_rates, clen);
117                 bss->supp_rates_len += clen;
118         }
119
120         bss->wmm_used = elems->wmm_param || elems->wmm_info;
121
122         if (!beacon)
123                 bss->last_probe_resp = jiffies;
124
125         return bss;
126 }
127
128 void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data *sdata, u8 *bssid,
129                              int freq, u8 *ssid, u8 ssid_len)
130 {
131         struct ieee80211_bss *bss;
132         struct ieee80211_local *local = sdata->local;
133
134         bss = ieee80211_rx_bss_get(local, bssid, freq, ssid, ssid_len);
135         if (bss) {
136                 cfg80211_unlink_bss(local->hw.wiphy, (void *)bss);
137                 ieee80211_rx_bss_put(local, bss);
138         }
139 }
140
141 ieee80211_rx_result
142 ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
143                   struct ieee80211_rx_status *rx_status)
144 {
145         struct ieee80211_mgmt *mgmt;
146         struct ieee80211_bss *bss;
147         u8 *elements;
148         struct ieee80211_channel *channel;
149         size_t baselen;
150         int freq;
151         __le16 fc;
152         bool presp, beacon = false;
153         struct ieee802_11_elems elems;
154
155         if (skb->len < 2)
156                 return RX_DROP_UNUSABLE;
157
158         mgmt = (struct ieee80211_mgmt *) skb->data;
159         fc = mgmt->frame_control;
160
161         if (ieee80211_is_ctl(fc))
162                 return RX_CONTINUE;
163
164         if (skb->len < 24)
165                 return RX_DROP_MONITOR;
166
167         presp = ieee80211_is_probe_resp(fc);
168         if (presp) {
169                 /* ignore ProbeResp to foreign address */
170                 if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
171                         return RX_DROP_MONITOR;
172
173                 presp = true;
174                 elements = mgmt->u.probe_resp.variable;
175                 baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
176         } else {
177                 beacon = ieee80211_is_beacon(fc);
178                 baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
179                 elements = mgmt->u.beacon.variable;
180         }
181
182         if (!presp && !beacon)
183                 return RX_CONTINUE;
184
185         if (baselen > skb->len)
186                 return RX_DROP_MONITOR;
187
188         ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
189
190         if (elems.ds_params && elems.ds_params_len == 1)
191                 freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
192         else
193                 freq = rx_status->freq;
194
195         channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
196
197         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
198                 return RX_DROP_MONITOR;
199
200         bss = ieee80211_bss_info_update(sdata->local, rx_status,
201                                         mgmt, skb->len, &elems,
202                                         channel, beacon);
203         if (bss)
204                 ieee80211_rx_bss_put(sdata->local, bss);
205
206         dev_kfree_skb(skb);
207         return RX_QUEUED;
208 }
209
210 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
211 {
212         struct ieee80211_local *local = hw_to_local(hw);
213         struct ieee80211_sub_if_data *sdata;
214
215         if (WARN_ON(!local->hw_scanning && !local->sw_scanning))
216                 return;
217
218         if (WARN_ON(!local->scan_req))
219                 return;
220
221         if (local->scan_req != &local->int_scan_req)
222                 cfg80211_scan_done(local->scan_req, aborted);
223         local->scan_req = NULL;
224
225         local->last_scan_completed = jiffies;
226
227         if (local->hw_scanning) {
228                 local->hw_scanning = false;
229                 /*
230                  * Somebody might have requested channel change during scan
231                  * that we won't have acted upon, try now. ieee80211_hw_config
232                  * will set the flag based on actual changes.
233                  */
234                 ieee80211_hw_config(local, 0);
235                 goto done;
236         }
237
238         local->sw_scanning = false;
239         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
240
241         netif_tx_lock_bh(local->mdev);
242         netif_addr_lock(local->mdev);
243         local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC;
244         local->ops->configure_filter(local_to_hw(local),
245                                      FIF_BCN_PRBRESP_PROMISC,
246                                      &local->filter_flags,
247                                      local->mdev->mc_count,
248                                      local->mdev->mc_list);
249
250         netif_addr_unlock(local->mdev);
251         netif_tx_unlock_bh(local->mdev);
252
253         mutex_lock(&local->iflist_mtx);
254         list_for_each_entry(sdata, &local->interfaces, list) {
255                 if (!netif_running(sdata->dev))
256                         continue;
257
258                 /* Tell AP we're back */
259                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
260                         if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
261                                 ieee80211_send_nullfunc(local, sdata, 0);
262                                 netif_tx_wake_all_queues(sdata->dev);
263                         }
264                 } else
265                         netif_tx_wake_all_queues(sdata->dev);
266
267                 /* re-enable beaconing */
268                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
269                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
270                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
271                         ieee80211_if_config(sdata,
272                                             IEEE80211_IFCC_BEACON_ENABLED);
273         }
274         mutex_unlock(&local->iflist_mtx);
275
276  done:
277         ieee80211_mlme_notify_scan_completed(local);
278         ieee80211_ibss_notify_scan_completed(local);
279         ieee80211_mesh_notify_scan_completed(local);
280 }
281 EXPORT_SYMBOL(ieee80211_scan_completed);
282
283 void ieee80211_scan_work(struct work_struct *work)
284 {
285         struct ieee80211_local *local =
286                 container_of(work, struct ieee80211_local, scan_work.work);
287         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
288         struct ieee80211_channel *chan;
289         int skip, i;
290         unsigned long next_delay = 0;
291
292         /*
293          * Avoid re-scheduling when the sdata is going away.
294          */
295         if (!netif_running(sdata->dev))
296                 return;
297
298         switch (local->scan_state) {
299         case SCAN_SET_CHANNEL:
300                 /* if no more bands/channels left, complete scan */
301                 if (local->scan_channel_idx >= local->scan_req->n_channels) {
302                         ieee80211_scan_completed(local_to_hw(local), false);
303                         return;
304                 }
305                 skip = 0;
306                 chan = local->scan_req->channels[local->scan_channel_idx];
307
308                 if (chan->flags & IEEE80211_CHAN_DISABLED ||
309                     (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
310                      chan->flags & IEEE80211_CHAN_NO_IBSS))
311                         skip = 1;
312
313                 if (!skip) {
314                         local->scan_channel = chan;
315                         if (ieee80211_hw_config(local,
316                                                 IEEE80211_CONF_CHANGE_CHANNEL))
317                                 skip = 1;
318                 }
319
320                 /* advance state machine to next channel/band */
321                 local->scan_channel_idx++;
322
323                 if (skip)
324                         break;
325
326                 next_delay = IEEE80211_PROBE_DELAY +
327                              usecs_to_jiffies(local->hw.channel_change_time);
328                 local->scan_state = SCAN_SEND_PROBE;
329                 break;
330         case SCAN_SEND_PROBE:
331                 next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
332                 local->scan_state = SCAN_SET_CHANNEL;
333
334                 if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
335                     !local->scan_req->n_ssids)
336                         break;
337                 for (i = 0; i < local->scan_req->n_ssids; i++)
338                         ieee80211_send_probe_req(
339                                 sdata, NULL,
340                                 local->scan_req->ssids[i].ssid,
341                                 local->scan_req->ssids[i].ssid_len,
342                                 local->scan_req->ie, local->scan_req->ie_len);
343                 next_delay = IEEE80211_CHANNEL_TIME;
344                 break;
345         }
346
347         queue_delayed_work(local->hw.workqueue, &local->scan_work,
348                            next_delay);
349 }
350
351
352 int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
353                          struct cfg80211_scan_request *req)
354 {
355         struct ieee80211_local *local = scan_sdata->local;
356         struct ieee80211_sub_if_data *sdata;
357
358         if (!req)
359                 return -EINVAL;
360
361         if (local->scan_req && local->scan_req != req)
362                 return -EBUSY;
363
364         local->scan_req = req;
365
366         /* MLME-SCAN.request (page 118)  page 144 (11.1.3.1)
367          * BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS
368          * BSSID: MACAddress
369          * SSID
370          * ScanType: ACTIVE, PASSIVE
371          * ProbeDelay: delay (in microseconds) to be used prior to transmitting
372          *    a Probe frame during active scanning
373          * ChannelList
374          * MinChannelTime (>= ProbeDelay), in TU
375          * MaxChannelTime: (>= MinChannelTime), in TU
376          */
377
378          /* MLME-SCAN.confirm
379           * BSSDescriptionSet
380           * ResultCode: SUCCESS, INVALID_PARAMETERS
381          */
382
383         if (local->sw_scanning || local->hw_scanning) {
384                 if (local->scan_sdata == scan_sdata)
385                         return 0;
386                 return -EBUSY;
387         }
388
389         if (local->ops->hw_scan) {
390                 int rc;
391
392                 local->hw_scanning = true;
393                 rc = local->ops->hw_scan(local_to_hw(local), req);
394                 if (rc) {
395                         local->hw_scanning = false;
396                         return rc;
397                 }
398                 local->scan_sdata = scan_sdata;
399                 return 0;
400         }
401
402         local->sw_scanning = true;
403
404         mutex_lock(&local->iflist_mtx);
405         list_for_each_entry(sdata, &local->interfaces, list) {
406                 if (!netif_running(sdata->dev))
407                         continue;
408
409                 /* disable beaconing */
410                 if (sdata->vif.type == NL80211_IFTYPE_AP ||
411                     sdata->vif.type == NL80211_IFTYPE_ADHOC ||
412                     sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
413                         ieee80211_if_config(sdata,
414                                             IEEE80211_IFCC_BEACON_ENABLED);
415
416                 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
417                         if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
418                                 netif_tx_stop_all_queues(sdata->dev);
419                                 ieee80211_send_nullfunc(local, sdata, 1);
420                         }
421                 } else
422                         netif_tx_stop_all_queues(sdata->dev);
423         }
424         mutex_unlock(&local->iflist_mtx);
425
426         local->scan_state = SCAN_SET_CHANNEL;
427         local->scan_channel_idx = 0;
428         local->scan_sdata = scan_sdata;
429         local->scan_req = req;
430
431         netif_addr_lock_bh(local->mdev);
432         local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
433         local->ops->configure_filter(local_to_hw(local),
434                                      FIF_BCN_PRBRESP_PROMISC,
435                                      &local->filter_flags,
436                                      local->mdev->mc_count,
437                                      local->mdev->mc_list);
438         netif_addr_unlock_bh(local->mdev);
439
440         /* TODO: start scan as soon as all nullfunc frames are ACKed */
441         queue_delayed_work(local->hw.workqueue, &local->scan_work,
442                            IEEE80211_CHANNEL_TIME);
443
444         return 0;
445 }
446
447
448 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
449                            struct cfg80211_scan_request *req)
450 {
451         struct ieee80211_local *local = sdata->local;
452         struct ieee80211_if_managed *ifmgd;
453
454         if (!req)
455                 return -EINVAL;
456
457         if (local->scan_req && local->scan_req != req)
458                 return -EBUSY;
459
460         local->scan_req = req;
461
462         if (sdata->vif.type != NL80211_IFTYPE_STATION)
463                 return ieee80211_start_scan(sdata, req);
464
465         /*
466          * STA has a state machine that might need to defer scanning
467          * while it's trying to associate/authenticate, therefore we
468          * queue it up to the state machine in that case.
469          */
470
471         if (local->sw_scanning || local->hw_scanning) {
472                 if (local->scan_sdata == sdata)
473                         return 0;
474                 return -EBUSY;
475         }
476
477         ifmgd = &sdata->u.mgd;
478         set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
479         queue_work(local->hw.workqueue, &ifmgd->work);
480
481         return 0;
482 }